Piano frame and bridge bar therefor



June 14, 1966 c. w. ANDERSEN 3,25

PIANO FRAME AND BRIDGE BAR THEREFOR Filed July 1. 1963 INVENTOR.

United States Patent Ohio Filed July 1, 1963, Ser. No. 291,929 2 Claims.(Cl. 84209) This invention relates generally to struck-string pianos andanalogous musical instruments and relates more particularly to anarrangement for mounting the strings of such instruments.

According to conventional practice, the strings of a piano are stretchedacross a frame; and spaced bars or bridges are raised from the frame toengage the strings and determine the vibrating length thereof. Aconsiderable problem resides in preserving the lateral position of thestrings. For example, a displaced string can easily come intovibrational contact with an adjacent string whereby to develop spurioussounds; and in addition, a string may become so extremely displacedlaterally as to be out of alignment with the percussive path of itsstriking hammer. Complete failure to sound such a string results. In thepast, it has been proposed to solve the p-noblem of string displacementby notching the upper bridge bar; but this notching of the upper bridgebar has been found to make the string sing or generate undesirablesounds.

Therefore, an important object of the present invention is to providemeans for laterally locating a piano string in full preservation of itsdesired vibrational characteristics.

A more general object of the invention is to provide a new and improvedpiano frame arrangement and bridge bar therefor.

These and other objects and features of the invention will become moreapparent from a consideration of the following description.

A piano frame arrangement in accord with the invention includes spacedbridge bars adapted to define therebetween the vibrating span of a pianostring. In compliance with the invention, a format-ion defining a notchis disposed adjacent one of the bridge bars outside of the space betweenthe bridge bars for controlling the position of a piano string situatedinterjacent the walls of the notch.

In order that the principle of the invention may be read- Patented June14, 1966 ICC Depression of the forward end of piano key lever 22 isarranged to cause a striking of the corresponding piano string throughone of the individual actionrnechanisms incorporated in the actionassembly :16. The individual action mechanism associated with the keylever 22 is indicated generally by the numeral 32. A main rail 34, ahammer rail .36 and a regulating rail 38 extend through the body of thepiano structure 10 to support and cooperate with each of the actionmechanisms 32, action brackets 40 and tubular action spacers 142 beingused to mount the rails 34, 36 and 38 in place.

The action mechanism 32 includes a hammer 44 that is mounted to a buttknuckle 46 by a hammer shank 48, the butt knuckle 46 being pivotallymounted to the main rail 34 by a butt flange '50. Depression of thepiano key lever .22 is arranged to actuate hammer 44 by means of asticker or abstract 52 that is detachably aflixed at one end of the keylever 22 by means of a coupling arrangement 54. The sticker 52 isswingably mounted at its other end to a whip 56, and the whip 56 ispivotally mounted to the main rail 34 by a whip flange 58. A fly or jack60 is pivotally mounted to the whip 56 by a fly flange 62. The head offly 60 engages a cushioned surface on the butt knuckle 46, and a feltcovered regulating rail button 64 is mounted to regulating rail 38 forcooperative engagement with a heel portion 66 of the fly 60. Depressionof the piano key lever 22 causes the sticker 52 to rise with a resultantpivoting of the whip 56. Engagement of the heel portion 66 of the flywith the regulating rail button 64 impels the hammer 44 into percussiveengagement with a correspondingpiano string 68 that is mounted on thepiano frame 14.

A partially felt-surfaced backcheck 70 is fastened to the Whip 56 inupstanding relationship by means of a backcheck wire or rod 72; and acooperatively felt-surfaced catcher 74 is secured to the butt knuckle 46by means of a catcher stem or shank 76 which radiates from the buttknuckle. The action mechanism. 32 also includes a metal spoon 78 whichis affixed to the whip 56 in upstanding relationship, being disposed onthe end of the whip which is opposite the connection with abstract 52.Upon actuation of the whip 56 by means of the key ily understood, asingle embodiment thereof applied to an upright piano, but to which theapplication .is not to be restricted, is shown in the accompanyingdrawing wherein:

FIG. 1 is a central sectional view taken through an upright piano toshow the operating elements thereof, including a piano frame arrangementconstructed in compliance with the invention;

FIG. 2 is a perspective View on an enlarged scale of the piano framearrangement of FIG. 1; and

FIG. 3 is an enlarged perspective view of the piano frame arrangement ofFIG. 2, showing in particular the notch formed in the auxiliary bridgebar.

Referring now in detail to the drawing, specifically to FIG. 1, anupright p'iano structure indicated generally by the numeral 10 will beseen to include a keyboard 12, a piano string frame 14 and an actionassembly 16. The keyboard 12 includes a keybed 18, a keyframe 20 and anumber of key levers such as key lever 22. The keyframe 20 is mounted onthe keybed 18 and includes a balance rail 24 into which upstandingbalance rail pins 26 are inserted. Each key lever 22 is slotted toreceive a balance rail pin 26 for fulcruming the key lever; and thekeyframe 20 also includes a back rail 28 to which a of the key lever 22.

lever 22, the spoon 78 contacts the lower, felt-surfaced end of a damperlever 80, damper lever. 80 being swingably mounted to the main rail 34by means of a damper lever flange 82. The spoon 78 is specificallyarranged to operate damper lever 80 so as to retract a damper head 84from contact with the piano string 68 immediately in advance of thehammer 44 striking the string.

The piano string frame 14 is ordinarily fabricated from steel andincludes an upper frame section 86 and a lower frame section 88 which isspaced from the upper frame section. In order to provide mounting sitesfor the piano string 68, a hitch pin 90 is mounted in the lower framesection 88 and a bore 92 is fashioned in the upper frame section 86spaced from the hitch pin to receive a tuning pin 94. The piano string68 includes a loop end 96 which is fitted over the hitch pin 90, theopposite end of the piano string 68 being attached to the tuning pin 94in a wrapped manner. The upper frame section 86 is provided with anupper frame bridge bar or abutment forma tion 98, and the lower framesection 88 is provided with a lower frame bridge bar or abutmentformation 100,

bridge bars 98 and 100 being appropriately spaced apart board bridge 106is mounted to the soundboard 104 in physical contact with the pianostring 68 to couple the vibration of the string to the soundboard.Bridge pins 108 are mounted on the soundboard bridge 106 on oppositelateral sides of the piano string 68 to preserve the lateral positioningof the lower end of the string.

Turning to a consideration of FIG. 2, the bridge bars 98 and 100 areseen to define elongated members of triangular section, each of theelongated bridge bars 98 and 100 including an apical ridge 110 forcontacting transversely and supporting a plurality of the piano strings68. In compliance with an important feature of the invention, anauxiliary bridge bar or abutment formation 112 is raised from the upperframe section 86 closely adjacent the bridge bar 98. The auxiliarybridge bar 112 is fashioned to be an elongated member of substantiallytriangular section, and the auxiliary bridge bar 112 is specificallyarranged to include an apical ridge 114 which is fashioned with a seriesof spaced notches 116 out therein. Each notch 116 is fashioned withclosely spaced, substantially parallel walls 118, as is best shown inFIG. 3; and each notch 116 is selected to take a depth which isappropriate for receiving a piano string 68 therein, the walls 118 ofthe notch controlling the lateral position of the piano string.

The auxiliary bridge bar 112 is located closely adjacent the bridge bar98 and is, in addition, situated outside of the space which is definedbetween the bridge bars 98 and 100. Thus, the auxiliary bridge bar 112does not contact the piano string along the vibrating span of itslength. With the auxiliary bridge bar so positioned, the notches thereinhave been found to be eminently useful in locating a piano stringlaterally. Moreover, the auxiliary bridge bar 112 serves to locate thepiano string at a position closely adjacent the point thereof which isintended to be struck by the hammer 44. Accordingly, the instantinvention assures proper striking of the string by its hammer.

The specific example herein shown and described is to be considered asprimarily illustrative. Various changes in structure will, no doubt,occur to those skilled in the art; and such changes are to be understoodas forming a part of this invention insofar as they fall within thespirit and scope of the appended claims.

The invention is claimed as follows:

1. In a piano frame arrangement, the combination comprising: a one-piecestring plate including a lower frame section and a upper frame sectionfixedly spaced from said lower frame section; a first elongated bridgebar formed integrally with said lower frame section and adapted tocontact transversely and support a plurality of piano strings; a secondelongated bridge bar formed integrally with said upper frame section andhaving spaced notches therein for receiving and laterally locating saidstrings; and a third elongated bridge bar formed integrally with saidupper frame section closely adjacent said second bridge "bar andintermediate said first and second bridge bars for cooperating with saidfirst bridge bar inpositively defining the vibrating span of said pianostrings.

2. In a piano frame arrangement, the combination according to claim 1wherein said bridge bars are of triangular section, said bridge barsbeing oriented for contacting the piano strings with an apical ridge.

References Qited by the Examiner UNITED STATES PATENTS LEO SMILOW,Primary Examiner.

C. M. OVERBEY, Assistant Examiner.

1. N A PIANO FRAME ARRANGEMENT, THE COMBINATION COMPRISING: A ONE-PIECESTRING PLATE INCLUDING A LOWER FRAME SECTION AND A UPPER FRAME SECTIONFIXEDLY SPACED FROM SAID LOWER FRAME SECTION; A FIXED ELONGATED BRIDGEBAR FORMED INTEGRALLY WITH SAID LOWER FRAME SECTION AND ADAPTED TOCONTACT TRANSVERSELY AND SUPPORT A PLURALITY OF PIANO STRINGS; A SECONDELONGATED BRIDGE BAR FORMED INTEGRALLY WITH SAID UPPER FRAME SECTION ANDHAVING SPACED NOTCHES THEREIN FOR RECEIVING AND LATERALLY LOCATING SAIDSTRINGS; AND A THIRD ELONGATED BRIDGE BAR FORMED INTEGRALLY WITH SAIDUPPER FRAME SECTION CLOSELY ADJACENT SAID SECOND BRIDGE BAR ANDINTERMEDIATE SAID FIRST AND SECOND BRIDGE BARS FOR COOPERATING WITH SAIDFIRST BRIDGE BAR IN POSITIVELY DEFINING THE VIBRATING SPAN OF SAID PIANOSTRINGS.